Many companies are trying to increase their customer satisfaction, improve their system's performance and gain a competitive advantage by using different quality programs such as Six Sigma, which proved to be one of the most effective. The objective of this project is to solve the problem of the inefficient use of insulation material in a famous duct manufacturing company in Kuwait by the use of Lean Six Sigma DMAIC approach. Company XYZ has been suffering from about 22% waste in the usage of its insulation material that corresponded to an average of more than $42,000 per year. This project will illustrate the details of the different phases of DMAIC to investigate and solve this problem, along with illustration of all the tools used including process mapping, capability analysis, sigma level assessment, Ishikawa diagram and brainstorming to uncover potential causes, and redesign the current fabrication process with the aid of software to help the company plan their production efficiently and fulfill orders more quickly. When a fabrication facility optimizes its use of insulation material/sheet metal, costs go down because there is less waste and productivity goes up because jobs take less time. Also, benefits can include increased job satisfaction among employees and more satisfied customers.T his study presents the impact of the Lean Six Sigma DMAIC on the company which will carry out a reduction in waste by 50% with a new sigma level of 4 instead of the current sigma level.